examples/vm_power_manager/oob_monitor_x86.c

   1 /* SPDX-License-Identifier: BSD-3-Clause
   2  * Copyright(c) 2018 Intel Corporation
   3  */
   4
   5 #include <unistd.h>
   6 #include <fcntl.h>
   7 #include <rte_log.h>
   8
   9 #include "oob_monitor.h"
  10 #include "power_manager.h"
  11 #include "channel_manager.h"
  12
  13 static volatile unsigned run_loop = 1;
  14 static uint64_t g_branches, g_branch_misses;
  15 static int g_active;
  16
  17 void branch_monitor_exit(void)
  18 {
  19         run_loop = 0;
  20 }
  21
  22 /* Number of microseconds between each poll */
  23 #define INTERVAL 100
  24 #define PRINT_LOOP_COUNT (1000000/INTERVAL)
  25 #define IA32_PERFEVTSEL0 0x186
  26 #define IA32_PERFEVTSEL1 0x187
  27 #define IA32_PERFCTR0 0xc1
  28 #define IA32_PERFCTR1 0xc2
  29 #define IA32_PERFEVT_BRANCH_HITS 0x05300c4
  30 #define IA32_PERFEVT_BRANCH_MISS 0x05300c5
  31
  32 static float
  33 apply_policy(int core)
  34 {
  35         struct core_info *ci;
  36         uint64_t counter;
  37         uint64_t branches, branch_misses;
  38         uint32_t last_branches, last_branch_misses;
  39         int hits_diff, miss_diff;
  40         float ratio;
  41         int ret;
  42
  43         g_active = 0;
  44         ci = get_core_info();
  45
  46         last_branches = ci->cd[core].last_branches;
  47         last_branch_misses = ci->cd[core].last_branch_misses;
  48
  49         ret = pread(ci->cd[core].msr_fd, &counter,
  50                         sizeof(counter), IA32_PERFCTR0);
  51         if (ret < 0)
  52                 RTE_LOG(ERR, POWER_MANAGER,
  53                                 "unable to read counter for core %u\n",
  54                                 core);
  55         branches = counter;
  56
  57         ret = pread(ci->cd[core].msr_fd, &counter,
  58                         sizeof(counter), IA32_PERFCTR1);
  59         if (ret < 0)
  60                 RTE_LOG(ERR, POWER_MANAGER,
  61                                 "unable to read counter for core %u\n",
  62                                 core);
  63         branch_misses = counter;
  64
  65
  66         ci->cd[core].last_branches = branches;
  67         ci->cd[core].last_branch_misses = branch_misses;
  68
  69         hits_diff = (int)branches - (int)last_branches;
  70         if (hits_diff <= 0) {
  71                 /* Likely a counter overflow condition, skip this round */
  72                 return -1.0;
  73         }
  74
  75         miss_diff = (int)branch_misses - (int)last_branch_misses;
  76         if (miss_diff <= 0) {
  77                 /* Likely a counter overflow condition, skip this round */
  78                 return -1.0;
  79         }
  80
  81         g_branches = hits_diff;
  82         g_branch_misses = miss_diff;
  83
  84         if (hits_diff < (INTERVAL*100)) {
  85                 /* Likely no workload running on this core. Skip. */
  86                 return -1.0;
  87         }
  88
  89         ratio = (float)miss_diff * (float)100 / (float)hits_diff;
  90
  91         if (ratio < ci->branch_ratio_threshold)
  92                 power_manager_scale_core_min(core);
  93         else
  94                 power_manager_scale_core_max(core);
  95
  96         g_active = 1;
  97         return ratio;
  98 }
  99
 100 int
 101 add_core_to_monitor(int core)
 102 {
 103         struct core_info *ci;
 104         char proc_file[UNIX_PATH_MAX];
 105         int ret;
 106
 107         ci = get_core_info();
 108
 109         if (core < ci->core_count) {
 110                 long setup;
 111
 112                 snprintf(proc_file, UNIX_PATH_MAX, "/dev/cpu/%d/msr", core);
 113                 ci->cd[core].msr_fd = open(proc_file, O_RDWR | O_SYNC);
 114                 if (ci->cd[core].msr_fd < 0) {
 115                         RTE_LOG(ERR, POWER_MANAGER,
 116                                         "Error opening MSR file for core %d "
 117                                         "(is msr kernel module loaded?)\n",
 118                                         core);
 119                         return -1;
 120                 }
 121                 /*
 122                  * Set up branch counters
 123                  */
 124                 setup = IA32_PERFEVT_BRANCH_HITS;
 125                 ret = pwrite(ci->cd[core].msr_fd, &setup,
 126                                 sizeof(setup), IA32_PERFEVTSEL0);
 127                 if (ret < 0) {
 128                         RTE_LOG(ERR, POWER_MANAGER,
 129                                         "unable to set counter for core %u\n",
 130                                         core);
 131                         return ret;
 132                 }
 133                 setup = IA32_PERFEVT_BRANCH_MISS;
 134                 ret = pwrite(ci->cd[core].msr_fd, &setup,
 135                                 sizeof(setup), IA32_PERFEVTSEL1);
 136                 if (ret < 0) {
 137                         RTE_LOG(ERR, POWER_MANAGER,
 138                                         "unable to set counter for core %u\n",
 139                                         core);
 140                         return ret;
 141                 }
 142                 /*
 143                  * Close the file and re-open as read only so
 144                  * as not to hog the resource
 145                  */
 146                 close(ci->cd[core].msr_fd);
 147                 ci->cd[core].msr_fd = open(proc_file, O_RDONLY);
 148                 if (ci->cd[core].msr_fd < 0) {
 149                         RTE_LOG(ERR, POWER_MANAGER,
 150                                         "Error opening MSR file for core %d "
 151                                         "(is msr kernel module loaded?)\n",
 152                                         core);
 153                         return -1;
 154                 }
 155                 ci->cd[core].oob_enabled = 1;
 156         }
 157         return 0;
 158 }
 159
 160 int
 161 remove_core_from_monitor(int core)
 162 {
 163         struct core_info *ci;
 164         char proc_file[UNIX_PATH_MAX];
 165         int ret;
 166
 167         ci = get_core_info();
 168
 169         if (ci->cd[core].oob_enabled) {
 170                 long setup;
 171
 172                 /*
 173                  * close the msr file, then reopen rw so we can
 174                  * disable the counters
 175                  */
 176                 if (ci->cd[core].msr_fd != 0)
 177                         close(ci->cd[core].msr_fd);
 178                 snprintf(proc_file, UNIX_PATH_MAX, "/dev/cpu/%d/msr", core);
 179                 ci->cd[core].msr_fd = open(proc_file, O_RDWR | O_SYNC);
 180                 if (ci->cd[core].msr_fd < 0) {
 181                         RTE_LOG(ERR, POWER_MANAGER,
 182                                         "Error opening MSR file for core %d "
 183                                         "(is msr kernel module loaded?)\n",
 184                                         core);
 185                         return -1;
 186                 }
 187                 setup = 0x0; /* clear event */
 188                 ret = pwrite(ci->cd[core].msr_fd, &setup,
 189                                 sizeof(setup), IA32_PERFEVTSEL0);
 190                 if (ret < 0) {
 191                         RTE_LOG(ERR, POWER_MANAGER,
 192                                         "unable to set counter for core %u\n",
 193                                         core);
 194                         return ret;
 195                 }
 196                 setup = 0x0; /* clear event */
 197                 ret = pwrite(ci->cd[core].msr_fd, &setup,
 198                                 sizeof(setup), IA32_PERFEVTSEL1);
 199                 if (ret < 0) {
 200                         RTE_LOG(ERR, POWER_MANAGER,
 201                                         "unable to set counter for core %u\n",
 202                                         core);
 203                         return ret;
 204                 }
 205
 206                 close(ci->cd[core].msr_fd);
 207                 ci->cd[core].msr_fd = 0;
 208                 ci->cd[core].oob_enabled = 0;
 209         }
 210         return 0;
 211 }
 212
 213 int
 214 branch_monitor_init(void)
 215 {
 216         return 0;
 217 }
 218
 219 void
 220 run_branch_monitor(void)
 221 {
 222         struct core_info *ci;
 223         int print = 0;
 224         float ratio;
 225         int printed;
 226         int reads = 0;
 227
 228         ci = get_core_info();
 229
 230         while (run_loop) {
 231
 232                 if (!run_loop)
 233                         break;
 234                 usleep(INTERVAL);
 235                 int j;
 236                 print++;
 237                 printed = 0;
 238                 for (j = 0; j < ci->core_count; j++) {
 239                         if (ci->cd[j].oob_enabled) {
 240                                 ratio = apply_policy(j);
 241                                 if ((print > PRINT_LOOP_COUNT) && (g_active)) {
 242                                         printf("  %d: %.4f {%lu} {%d}", j,
 243                                                         ratio, g_branches,
 244                                                         reads);
 245                                         printed = 1;
 246                                         reads = 0;
 247                                 } else {
 248                                         reads++;
 249                                 }
 250                         }
 251                 }
 252                 if (print > PRINT_LOOP_COUNT) {
 253                         if (printed)
 254                                 printf("\n");
 255                         print = 0;
 256                 }
 257         }
 258 }